accel/rocket: fix unwinding in error path in rocket_probe

accel/rocket: fix unwinding in error path in rocket_probe

When rocket_core_init() fails (as could be the case with EPROBE_DEFER),
we need to properly unwind by decrementing the counter we just
incremented and if this is the first core we failed to probe, remove the
rocket DRM device with rocket_device_fini() as well. This matches the
logic in rocket_remove(). Failing to properly unwind results in
out-of-bounds accesses.

Fixes: 0810d5ad88a1 ("accel/rocket: Add job submission IOCTL")
Cc: stable@vger.kernel.org
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Tomeu Vizoso <tomeu@tomeuvizoso.net>
Signed-off-by: Tomeu Vizoso <tomeu@tomeuvizoso.net>
Link: https://patch.msgid.link/20251215-rocket-error-path-v1-2-eec3bf29dc3b@cherry.de